1. Field of the Invention
The present invention relates to an extracting apparatus and a tension-keeping method of a power supply cord in a robot, by which the cord can always maintain a predetermined force of tension regardless of a distance between the robot and an outlet.
2. Description of Prior Art
In a conventional robot, in order to pull out an cord from the robot, the cord is forcibly extracted. In order to retract the cord into the robot, a push button is pressed to thereby cause the cord to be drawn into the robot at a high speed by force of a spiral plate spring therein.
Although most self-propelled robotic vacuum cleaners come in cordless styles, in some self-propelled corded cleaners, the cord should maintain a straight line between the cleaner and the outlet, so that the cord cannot be a hindrance to travelling of the robot. Accordingly, in a conventional self-propelled corded cleaner equipped with a push-button switch for an cord operation, there is a shortcoming in that when the cleaner travels near the electric outlet, it may run over the cord.
Furthermore there has been another problem in that, the more a distance between the cleaner and the outlet is increased, the more tension is given to the cord by the spiral plate spring, thereby resulting in a generation of uncleaned region of space caused by immobilization of the robotic cleaner by an excessively tensioned cord.
Accordingly, the present invention has been proposed to solve the above problems and it is an object of the present invention to maintain a predetermined force of tension on an cord at all times regardless of a distance between a robot and an outlet, so that travel of the robot can be facilitated and the robot can clean all the cleaning area.